Comparing interventions using NNT — Flashcards

Flashcard 1: The Mortality Rate measures the _____ due to a specific disease in a population at risk

Answer: speed of death

Flashcard 2: What is the formula for calculating **Attributable Risk** (AR)?

Answer: AR = [a / (a + b)] – [c / (c + d)] (Incidence in exposed – Incidence in unexposed)

Extra: Attributable Risk (AR) is the difference in risk between the exposed group and the unexposed group. In a standard 2x2 table: • a = Exposed, Disease (+) • b = Exposed, Disease (-) • c = Unexposed, Disease (+) • d = Unexposed, Disease (-) AR = [a / (a + b)] – [c / (c + d)]

Flashcard 3: _____ risk reduction is the proportion of risk reduction attributable to an intervention compared to a control

Answer: Relative

Flashcard 4: The number needed to harm (NNH) is equal to _____

Answer: 1/AR

Flashcard 5: Cumulative incidence = (# of new cases over a specific period) / (number of people at risk at the _____ of the period)

Answer: beginning

Flashcard 6: attributable risk/absolute risk reduction (epidemiology)

Answer: the difference in risk between exposed and unexposed groups (attributable risk used for risk-enhancing factors ARR used for risk-reducing interventions)

Flashcard 7: number needed to harm (NNH) (epidemiology)

Answer: The number of patients who must be exposed in order to cause 1 event.

Extra: NNH = 1/attributable risk

Flashcard 8: number needed to treat (NNT) (epidemiology)

Answer: The number of patients who must be treated in order to prevent 1 event.

Extra: NNT = 1/absolute risk reduction